title: The anti-aging factor α-klotho during human pregnancy and its expression in pregnancies complicated by small-for-gestational-age neonates and/or preeclampsia.
abstract: OBJECTIVE
  α-klotho, a protein with anti-aging properties, has been involved in important biological processes, such as calcium/phosphate metabolism, resistance to oxidative stress, and nitric oxide production in the endothelium. Recent studies have suggested a role of α-klotho in endocrine regulation of mineral metabolism and postnatal growth in infants. Yet, the role of α-klotho during pregnancy remains largely unknown. The aim of this study was to determine whether maternal plasma concentration of α-klotho changes during pregnancy and evaluate its expression in pregnancies complicated by small for gestational age (SGA) and/or preeclampsia (PE).
  
  
  METHODS
  This cross-sectional study included patients in the following groups: (1) non pregnant women (n = 37); (2) uncomplicated pregnancy (n = 130); (3) PE without an SGA neonate (PE; n = 58); (4) PE with an SGA neonate (PE and SGA; n = 52); and (5) SGA neonate without PE (SGA; n = 52). Plasma concentrations of α-klotho were determined by ELISA.
  
  
  RESULTS
  The median plasma α-klotho concentration was higher in pregnant than in non-pregnant women. Among women with an uncomplicated pregnancy, the median plasma concentration of α-klotho increased as a function of gestational age (Spearman Rho = 0.2; p = 0.006). The median (interquartile range) plasma concentration of α-klotho in women with PE and SGA [947.6 (762-2013) pg/mL] and SGA without PE [1000 (585-1567) pg/mL] were 21% and 17% lower than that observed in women with an uncomplicated pregnancy [1206.6 (894-2012) pg/mL], (p = 0.005 and p = 0.02), respectively. Additionally, there were no significant differences in the median plasma concentration of α-klotho between uncomplicated pregnancies and women with PE without an SGA neonate (p = 0.5).
  
  
  CONCLUSIONS
  Maternal plasma concentration of α-klotho was higher during pregnancy than in a non-pregnant state. Moreover, the median maternal plasma concentration of α-klotho was lower in mothers who delivered an SGA neonate than in those with an uncomplicated pregnancy regardless of the presence or absence of PE.
authors.affiliation: Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda , MD and Detroit, MI , USA .
authors.forename: Jezid
authors.initials: J
authors.lastname: Miranda
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Korzeniewski
authors.forename: Alyse G
authors.initials: AG
authors.lastname: Schwartz
authors.forename: Piya
authors.initials: P
authors.lastname: Chaemsaithong
authors.forename: Tamara
authors.initials: T
authors.lastname: Stampalija
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Zhong
authors.initials: Z
authors.lastname: Dong
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.forename: George P
authors.initials: GP
authors.lastname: Chrousos
authors.forename: Philip
authors.initials: P
authors.lastname: Gold
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D003430:Cross-Sectional Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000097:blood* / Q000000981:diagnostic imaging; D005865:Gestational Age; D005966:Glucuronidase / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D000090265:Klotho Proteins; D017078:Laser-Doppler Flowmetry; D011225:Pre-Eclampsia / Q000097:blood* / Q000000981:diagnostic imaging; D011247:Pregnancy / Q000097:blood*; D018608:Ultrasonography, Doppler; D014469:Umbilical Arteries / Q000000981:diagnostic imaging; D055988:Uterine Artery / Q000000981:diagnostic imaging; D055815:Young Adult
chemical_list: D005966:Glucuronidase; D000090265:Klotho Proteins